Evaluating Retinal Ganglion Cell Responses Under Temporal Interference-Based Suprachoroidal Stimulation

Suprachoroidal retinal prostheses, positioned between the sclera and choroid, offer advantages such as surgical simplicity and long-term stability. However, the relatively large distance between the electrodes and the retina results in elevated activation thresholds and limited spatial resolution of retinal ganglion cell (RGC) responses. To address these limitations, this study explores the use of temporal interference (TI) stimulation, a technique known to enable focal activation in deep neural tissues, to enhance suprachoroidal stimulation (SS). We propose a novel TI-suprachoroidal stimulation (TI-SS) strategy and evaluate its effectiveness using a finite element model of the human eye and a population RGC model. The study compares TI-SS and conventional multipolar SS in terms of RGC activation thresholds and spatial selectivity. Results show that, with the exception of the 0.5 s stimulation duration, 10 pulses per second (pps) condition, TI-SS consistently lowers RGC activation thresholds—achieving up to a 40% reduction at 1.5 s and 40 pps. Furthermore, TI-SS can improve spatial resolution of RGC receptive fields (RF) under properly configured stimulation parameters. These findings suggest that TI-SS is a promising approach to enhance the efficacy of suprachoroidal retinal prostheses by reducing activation thresholds and improving spatial specificity.